1-propen-2-yl phosphinothioates



3,070,488 i-PRGPEN-Z-YL PHGSPHINOTHIOATES Peter E. Newallis, Crestwood, and Joseph W. Baker and John P. Chupp, Kirkwood, Mo., assignors to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware No Drawing. Filed Jan. 25, 1960, Ser. No. 4,216 19 Claims. (Cl. 167-22) This invention relates to new and useful phosphinothioates and to methods of making same. Additionally this invention relates to insecticidal compositions containing the new phosphinothioates as an active ingredient.

The new compounds of this invention can be termed l-propen-Z-yl phosphinothioates and can be represented by the structure l OC=CAC--N l R (311g R wherein R, R, R, and R are like or unlike alkyl radicals containing from i to 4 carbon atoms (e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl and isobutyl) and wherein A is a halogen having an atomic number above 9 but not higher than 35 (i.e. chlorine or bromine,

wherein A, R and R have the above described significance, in the presence of an inert organic liquid or solvent (e.g. acetone, methyl ethyl ketone, benzene, toluene, xylene, carbon tetrachloride, ethyl acetate, isopropyl acetate, etc.) and a hydrogen halide scavenging agent (e.g. sodium carbonate, potassium carbonate, the tertiary organic amines such as triethylamine, tributylamine, dimethylaniline, pyridine, lutidine, l-methyl piperidine,

etc.) in an amount at least sufficient to absorb the hydrogen halide by product. The scavenging agent can be added in toto at the beginning of the reaction or throughout the course of the reaction. While a wide range of reaction temperatures can be employed provided the system is fluid (i.e. the temperature is maintained above the freezing point of the system and up to and including the boiling point of the system) it is preferred to employ a reaction temperature in the range of from about C. to about 120 C.

As illustrative of the preparation of the new compounds of this invention is the following:

Example I weight of dimethylphosphinothioic chloride, and. ap-

proximately 150 parts by weight of benzene. The mixture is then heated at reflux for 4 hours. The reaction mass is then cooled to room temperature and washed with four 150 parts by weight portions of water. The so-washed reaction mass is then subjected to vacuum distillation to remove the benzene. The residue, a white crystalline solid melting at lO7l08 C. is O-(l-diethylamido l-chloro-1-propen-2 yl) dimethylphosphinothioate which is soluble in acetone and benzene but insoluble in water.

Employing the above procedure but replacing dimethylphosphinothioic chloride with an equimolecular amount of diethylphosphinothioio chloride there is obtained 0-( l-diethylamido-l-chloro-1-propen-2 yl) diethylphosphinothioate which White solid material is insoluble in water.

Employing the above procedure of Example I but replacing Z-chloro-N,N-diethylacetoacetamide with an equimolecular amount of 2-bromo-N,N-dimethylacetoacetamide there is obtained O-(1-dimethylamido-l-bromo-lprOpen Z-yl) dimethylphosphinothioate which solid material is insoluble in water.

In the process of this invention any inert organic liquid or mixture of inert organic liquids can be used provided at least one of the reactants is soluble therein. The methods by which the phosphinothioates of this invention are isolated will vary slightly with the reactants employed and the product produced. Further purification by selec tive solvent extraction or by absorptive agents such as activated carbon or clays can precede the removal of the inert organic liquid or solvent. Additionally an inert organic solvent can be added to and in the purification by absorptive agents. However, the product is generally satisfactory for insecticidal purposes without further purification.

It will be understood that the terms insect and insecticide are used herein in their broad common usage to include spiders, mites, ticks, and like pests which are not in the strict biological sense classed as insects. Thus the usage herein conforms to the definitions provided by Congress in Public Law 104, the .Federal Insecticide, Fungicide, and Rodenticide Act of 1947, Section 2, subsection h, wherein the term insect is used to refer not only to those small invertebrate animals belonging mostly .to the class Insecta, comprising six-legged,

usually winged forms, as beetles, bugs, bees, flies, and soforth, but also to other allied classes of arthropods whose members are Wingless and usually have more than six legs, such vas spiders, mites, ticks, centipedes, and wood lice.

Of the new compounds those found to be particularly useful for insecticidal purposes are those of the structure wherein R, R, R", and R' are like or unlike alkyl radicals containing not more than two carbon atoms "(i.e. methyl or ethyl) and wherein A is a halogen having an atomic number above 9 but not higher than 35. As illustrative of the preferred phosphinothioates of this invention are the following:

O-( l-dimethylamido-1-chloro-1-propen-2-yl) dimethyl-,

phosphinothioate O- 1-dimethylamido-l-bromo-l-propen-Z-yl) diethylphosphinothioate ,O-( 1-dimethy1amido-1-bromo-l-propen-2-yl) dimethyl- =1 O-( l-diethylamidod-chloro-1-propen-2-yl) methylethylphosphinothioate These compounds can be prepared conveniently by reacting in an anhydrous system at a temperature in the. range of C. to 120 C. the appropriate phosphinothioic chloride with a substantially equimolecular amount of the appropriate 2-halo-N,N-dialkylacetoacetamide in the presence of an inert organic liquid or solvent and a hydrogen chloride scavenging agent in an amount at least sufficient to absorb the by-product hydrogen chloride.

As further illustrative of the phosphinothioates of this invention are the following:

O-(l-dirnethylamido-l-chloro-l-propen-2-yl) di-n-propylphosphinothioate O-(l-dimethylamido-l-chloro-l-propen-Z-yl) diisobutylphosphinothioate O-(1-diethylamido-l-bromo-l-propen-Z-yl) diisobutylphosphinothioate The phosphinothioates of this invention are effective against a wide variety of insect pests. As illustrative of the activity but not limitative thereof is the following:

One gram of O-(l-diethylamido l-chloro-l-propen-2- yl) dimethylphosphinothioate is dissolved in suificient acetone to make a concentrated solution thereof. Approximately 0.1 cc. of sorbitan monolaurate polyoxyethylene derivative (a commercial water-soluble non-ionic emulsifying agent) is then mixed with the concentrate. To this mixture and with agitation is added sufficient water to provide an aqueous emulsion having a concentration of 0.025% by weight of O-(l-diethylamido-lchloroA-propen-Z-yl) dimethylphosphinothioate. Thereupon lirna bean plant leaves previously infested with the two-spotted spider mite, Tetranychus zelarz'us (L.), are dipped in the aqueous emulsion, withdrawn, and set aside for observation. At the end of 48 hours a 100% kill of the mobile stages of the mite was noted. Seven days after setting the test specimen aside residual activity was confirmed, a 97% kill of both the resting stage and the ova stage being noted. Similar results against the mobile, resting and ova stages of the same mite are obtained employing O-(1-dimethylamido-1-chloro-1-propen-2-yl) diethylphosphinothioate.

Systemic activity was also observed against a wide variety of insects. For example against the two-spotted spider mite, T etranychus telarius (L.), a 75% kill was observed employing O.-( l-diethylamido-1-chloro-1-propen- 2-yl) dimethylphosphinothioate at a concentration of 0.004% by weight.

Although the phosphinothioates of this invention are useful per se in controlling a wide variety of insect pests, it is preferable that they be supplied to the pests or to the environment of the pest or pests in a dispersed form in a suitable extending agent.

In the instant specification and appended claims it is to be understood that the term dispersed is used in its widest possible sense. When it is said that the phosphinothioates of this invention are dispersed, it means that the particles of the phosphinothioates of this invention may be molecular in size and held in true solution in a suitable organic solvent. It means further, that the particles may be colloidal in size and distributed throughout a liquid phase in the form of suspensions of emulsions or in the form of particles held in suspension by wetting agents. It also includes particles which are distributed in a semisolid viscous carrier such as petrolatum or soap or other ointment base in which they may be actually dissolved in the semi-solid or held in suspension in the semi-solid with the aid of suitable wetting or emulsifying agents. The term dispersed also means that the particles may be mixed with and distributed throughout a solid carrier providing a mixture in particulate form, e.g., pellets, granules, powders, or dusts. The term dispersed also includes mixtures which are suitable for use as aerosols including solutions, suspensions, or emulsions of the phos- 4 phinothioates of this invention in a carrier such as dichlorodifiuoromethane and like fiuorochloroalkanes which boil below room temperature at atmospheric pressure.

In the instant specification and appended claims it is to he understood that the expression extending agent" includes any and all of those substances in which the phosphinothioates of this invention are dispersed. It includes, therefore, the solvents of a true solution, the liquid phase of suspensions, emulsions or aerosols, the semi-solid carrier of ointments and the solid phase of particulate solids, e.g. pellets, granules, dusts and powders.

The exact concentration of the phosphinothioates of this invention employed in combatting or controlling insect pests can vary considerably provided the required dosage (i.e. toxic or lethal amount) thereof is supplied to the pests or to the environment of the pests. When the extending agent is a liquid or mixture of liquids (e.g. as in solutions, suspensions, emulsions or aerosols) the concentration of the phosphinothioate employed to supply the desired dosage generally will be in the range of 0.001 to 50 percent by weight. When the extending agent is a semi-solid or solid, the concentration of the phosphinothioate employed to supply the desired dosage generally will be in the range of 0.1 to 25 percent by weight. From a practical point of view, the manufacturer must supply the agriculturist with a low-cost concentrate or spray base or particulate solid base in such form that, by merely mixing with water or solid extender (e.g. powdered clay or talc) or other low-cost material available to the agriculturist at the point of use, he will have an easily prepared insecticidal spray or particulate solid. In such a concentrate composition, the phosphinothioate generally will be present in a concentration of 5 to 95 percent by weight, the residue being any one or more of the well-known insecticidal adjuvants, such as the various surface-active agents (e.g., detergents, a soap or other emulsifying or wetting agent, surface-active clays), solvents, diluents, carrier media, adhesives, spreading agents, humectants, and the like.

There are a large number of organic liquids which can be used for the preparation of solutions, suspensions, or emulsions of the phosphinothioates of this invention. For example, isopropyl ether, acetone, methyl ethyl ketone, dioxane, cyclohexanone, carbon tetrachloride, ethylene dichloride, tetrachloroethane, hexane, heptane and like higher liquid alkanes, hydrogenated naphthalene, solvent naphtha, benzene, toluene, xylene, petroleum fractions (e.g. those boiling almost entirely under 400' F. at atmospheric pressure and having a flash point above about F., particularly kerosene), mineral oils having an unsulfonatable residue above about 80 percent and preferably above about percent. In those instances wherein there may be concern about the phytotoxicity of the organic liquid extending agent a portion of same be replaced by such low molecular weight aliphatic hydrocarbons as dipentene, diisobutylene, propylene trimer, and the like or suitable polar organic liquids such as the aliphatic ethers and the aliphatic ketones containing not more than about 10 carbon atoms as exemplified by acetone, methyl ethyl ketone, diisobutyl ketone, dioxane, isopropyl ether, and the like. In certain instances, it is advantageous to employ a mixture of organic liquids as the extending agent.

When the phosphinothioates of this invention are to be supplied to the insect pests or to the environment of the pests as aerosols, it is convenient to dissolve them in a suitable solvent and disperse the resulting solution in dichlorodifluoromethane or like chlorofluoroalkane which boils below room temperature at atmospheric pressure.

The phosphinothioates of this invention are preferably supplied to the insect pests or to the environment of the insect pests in the form of emulsions or suspensions. Emulsions or suspensions are prepared by dispersing the phosphinothioates of this invention either per se or in the form of an organic solution thereof in water with the aid of a water-soluble surfactant. The term surfactant as employed here and in the appended claims is used as in volume II of Schwartz, Perry and Bertchs Surface Active Agents and Detergents (1958, Interscience Publishers, Inc. New York) in place of the expression emulsifying agent to connote generically the various emulsifying agents, dispersing agents, wetting agents and spreading agents, that are adapted to be admixed with the active ingredients in the water vehicle or carrier in which they are insoluble through lowering the surface tension of the water (see also Frear Chemistry of Insecticides, Fungicides and Herbicides, second edition, page 280). These surfactants include the well-known capillary-active substances which may be anion-active (or anionic), cationactive (or cationic), or non-ionizing (or non-ionic) which are described in detail in volumes I and II of Schwartz, Perry and Berchs Surface Active Agents and Detergents (1958, Interscience Publishers, Inc., New York) and also in the November 1947 issue of Chemical Industries (pages 811-842) in an article entitled Synthetic Detergents by John W. McCutcheon and also in the July, August, September and October 1952 issues of Soap and Sanitary Chemicals under the title Synthetic Detergents. The disclosures of these articles with respect to surfactants, i.e. the anion-active, cation-active and non-ionizing capillary active substance, are incorporated in this specification by reference in order to avoid unnecessary enlargement of this specification; The preferred surfactants are the water-soluble anionic surface active agents and the water soluble non-ionic surface-active agents set forth in US. 2,846,398 (issued August 5, 1958). In general it is preferred that a mixture of water-soluble anionic and watersoluble non-ionic surfactants be employed.

The phosphinothioates of this invention can be dispersed by suitable methods (e.g., tumbling or grinding) in solid extending agents either of organic or inorganic nature and supplied to the insect pest environment in particulate form. Such solid materials include, for example, tricalcium phosphate, calcium carbonate, kaolin, bole, kieselguhr, talc, bentonite, fullers earth, pyrophillite, diatomaceous earth, calcined magnesia, volcanic ash, sulfur and the like inorganic solid materials, and include, for example, such materials of organic nature as powdered cork, powdered wood, and powdered walnut shells. The preferred solid carriers are the adsorbent clays, e.g. bentonite. These mixtures can be used for insecticidal purposes in the dry form, or, by addition of water-soluble surfactants or wetting agents the dry particulate solids can be rendered wettable by water so as to obtain stable aqeous dispersions or suspensions suitable for use as sprayable compositions.

For special purposes the phosphinothioates of this invention can be dispersed in a semi-solid extending agent such as petrolatum or soap (e.g., sodium stearate or oleate or palmitate or mixtures thereof) with or without the aid of solubility promotors and/or surfactants or dispersing agents.

In all of the forms described above the dispersions can be provided ready for use in combatting insect pests or they can be provided in a concentrated form suitable for mixing with or dispersing in other extending agents. As illustrative of a particularly useful concentrate is an intimate mixture of phosphinothioates of this invention with a water-soluble surfactant which lowers the surface tension of water in the weight proportions of 0.1 to parts of surfactant with sufficient of the phosphinothioate of this invention to make 100 parts by weight. Such a concentrate is particularly adapted to be made into a spray for combatting various forms of insect pests (particularly mites) by the addition of water thereo. As illustrative of such a concentrate is an intimate mixture of 95 parts by weight of O-(l-diethylamido-l-chloro-l-propene-Z-yl) dimethylphosphinothioate and 5 parts by weight of a watersoluble non-ionic surfactant such as the polyoxyethylene derivative of sorbitan monolaurate.

Another useful concentrate adapted to be made into a spray for combatting insect pests (particularly mites) is a solution (preferably as concentrated as possible) of a phos. phinothioate of this invention in an organic solvent therefor. The said liquid concentrate preferably contains dissolved therein a minor amount (e.g., 0.5 to 10 percent by weight of the weight of the new insecticidal agent) of a surfactant (or emulsifying agent), which surfactant is also water-soluble. As illustrative of such a concentrate is a solution of O-(l-dimethylamido-l-chloro-l-propen-Z- yl) diethylphosphinothioate in benzene which solution contains dissolved therein a water-soluble alkylaryl sulfonate anionic surfactant.

Of the surfactants aforementioned in preparing the various emulsifiable, wettable or dispersible compositions or concentrates of this invention, the anionic and nonionic surfactants are preferred. Of the anionic surfactants, the particularly preferred are the well known water-soluble alkylaryl sulfonates, e.g. sodium decylben: zene sulfonate andsodium dodecylbenzene sulfonate. Of the non-ionic surfactants, the particularly preferred are the water-soluble polyoxyethylene derivatives of alkylphenols (particularly isooctylphenol) and the water soluble polyoxyethylene derivatives of the mono-higher fatty acid esters of sorbitan.

In all of the various dispersions described hereinbefore for insecticidal purposes, the active ingredient can be one or moreof the compounds of this invention. The compounds of this invention can also be advantageously employed in combination with other pesticides, including, for example, nematocides, bactericides, fungicides, and herbicides. In this manner it is possible to obtain mixtures which are effective .againsta wide variety of pests and other forms of noxious life.

In controlling or combatting insect pests the phos! phinothioates of this invention either per se or compositions comprising same are supplied to the insect pests or to their environment in a lethal or toxic amount. This can be done by dispersing the new insecticidal agent or insecticidal composition comprising same in, on or over an infested environment or in or over an environment the insect pests frequent, e.g. agricultural soil or other growth media or other media infested with the insect pests of attractable to the pests for habitational or SUS- tenance or propagational purposes, in any conventional fashion which permits contact between the. insect pests and the phosphinothioates of this invention. Such dispersing can be brought about by applying the new phosphinothioates per se or sprays or particulate solid compositions containing same to a surface infested with the insect pests or-attractable to the pests, as for example, the surface of an agricultural soil or other media such as the above ground surface of plants by any of the conventional methods, e.g. power dusters, boom and hand sprayers, and spray dusters. Also for sub-surface application such dispersing can be carried out by simply mixing the new insecticidal spray per se or insecticidal agent or particulate solid composition comprising same with the infested environment or with the environment the insect pests frequent, or by employing a liquid carrier for the new insecticidal agent to accomplish sub-surface penetration and impregnation thereof therein.

While this invention has been described with respect to certain embodiments, it is to be understood that it is not so limited and that variations and modifications thereof obvious to those skilled in the art can be made without departing from the spirit or scope thereof.

What is claimed is:

1. Phosphinothioates of the structure from 1 to 4 carbon atoms and wherein A is a halogen having an atomic number above 9 but not higher than 35.

Ph h nmb t s f. e ar a \ii 'P- OC=CACN R! O i R! wherein R and R have the same significance as in claim 1 and wherein X means a halogen having an atomic number higher than 9 but not higher than 35, with a substantially equimolecular amount of an amide of the structure /RII CHa("1.C(A)H-t' N wherein A, R", and R have the same significance as in claim 1, in an anhydrous system in the presence of an inert organic liquid and a hydrogen halide scavenging agent.

7. The method of making the compounds of claim 2 which comprises reacting an acid chloride of the structure R s H P-Cl wherein R and R have the same significance as in claim 2 with a substantially equimolecular proportion of an amide of the structure wherein A, R" and R' have the same significance as in claim 2, in an anhydrous system in the presence of an inert organic liquid and a hydrogen chloride scavenging agent,

8. An insecticidal composition comprising a compound of claim 1 dispersed in an extending agent.

9. An insecticidal composition comprising a compound of claim 1 dispersed in a semi-solid extending agent, the composition containing 0.1 to 25 percent by weight of said compound of claim 1.

10. An insecticidal composition comprising a compound of claim 1 dispersed in a solid extending agent, the composition containing 0.1 to 25 percent by weight of said compound of claim 1.

11. An insecticidal composition comprising a compound of claim 1 dispersed in a liquid extending agent, the composition containing 0.001 to 50 percent by weight of said compound of claim 1.

12. An insecticidal composition comprising a compound of claim 2 dispersed in an adsorbent clay, the composition containing 0.1 to 25 percent by weight of said compound of claim 2.

13. An insecticidal concentrate comprising a compound of claim 2 and an insecticidal adjuvant, said concentrate containing from 5 to percent by weight of the compound of claim 2.

14. An insecticidal concentrate comprising a compound of claim 2 dispersed in an organic solvent therefor and having dissolved therein a minor amount of a surfactant, said concentrate forming an emulsion with water upon agitation therewith.

15. An insecticidal concentrate adapted to be made into a sprayable composition by the addition of water comprising a compound of claim 2 in admixture with a water-soluble surfactant in the weight proportion of 0.1 to 15 parts of surfactant and sufficient of said compound of claim 2 to make parts by weight.

16. The method of controlling insects which comprises contacting the insects with a toxic amount of a compound of claim 1.

17. The method of controlling insects which comprises contacting the insects with a toxic amount of a compound of claim 2.

18. The method of protection of plant against insect attack which comprises applying to the plant an insecticidal amount of at least one compound of claim 2.

19. The method of controlling insects which comprises contacting the insects with a toxic amount of a compound of claim 3.

References Cited in the file of this patent UNITED STATES PATENTS 2,668,822 Tolkmuth Feb. 9, 1954 2,891,059 Malz June 16, 1959 2,907,787 Hoffmann Oct. 6, 1959 2,908,605 Beriger Oct. 13, 1959 2,915,429 Scherer Dec. 1, 1959 2,920,993 Fairchild Ian. 12, 1960 

1.PHOSPHINOTHIOATES OF THE STRUCTURE 